The pilot attempted to take off into wind in a northwesterly direction, although the distance available to take off and clear a 50-foot obstacle was insufficient. After becoming airborne with insufficient distance remaining to clear the obstacles ahead, the pilot attempted a steep turn at low altitude, resulting in a stall and impact with the water.Findings as to Causes and Contributing Factors The pilot attempted to take off into wind in a northwesterly direction, although the distance available to take off and clear a 50-foot obstacle was insufficient. After becoming airborne with insufficient distance remaining to clear the obstacles ahead, the pilot attempted a steep turn at low altitude, resulting in a stall and impact with the water. During the step-taxi, figure-eight manoeuvre, because of the associated wind and wave conditions, the aircraft was at risk of capsizing. The aircraft was step-taxied in a manner that introduced a potential risk of collision with watercraft and other people using the lake. The figure-eight, take-off manoeuvre employed by the pilot further decreased the into-wind take-off distance available because of the large radius turn of the aircraft while on step. There is no indication that any of the pilot recency requirements under Paragraph401.05(2)(a) of the Canadian Aviation Regulations (CARs) were complied with.Findings as to Risk During the step-taxi, figure-eight manoeuvre, because of the associated wind and wave conditions, the aircraft was at risk of capsizing. The aircraft was step-taxied in a manner that introduced a potential risk of collision with watercraft and other people using the lake. The figure-eight, take-off manoeuvre employed by the pilot further decreased the into-wind take-off distance available because of the large radius turn of the aircraft while on step. There is no indication that any of the pilot recency requirements under Paragraph401.05(2)(a) of the Canadian Aviation Regulations (CARs) were complied with. Due to the absence of a maintenance release for the vortex generator installation, the aircraft was not being operated in accordance with Section605.85 of the CARs.Other Finding Due to the absence of a maintenance release for the vortex generator installation, the aircraft was not being operated in accordance with Section605.85 of the CARs.